diff --git a/frontend/src/App.vue b/frontend/src/App.vue
index 84c12b591..8d13ca90b 100644
--- a/frontend/src/App.vue
+++ b/frontend/src/App.vue
@@ -4,4 +4,44 @@
   </Suspense>
 </template>
 
-<script setup></script>
+<script setup>
+import { useTheme } from 'vuetify'
+import themeApi from '@/api/theme'
+
+const theme = useTheme()
+
+themeApi.getTheme().then((response) => {
+  if (
+    response.data.theme_primary_color !==
+    theme.themes.value.light.colors.primary
+  ) {
+    theme.themes.value.light.colors.primary = response.data.theme_primary_color
+  }
+  if (
+    response.data.theme_primary_color_light !==
+    theme.themes.value.light.colors['primary-lighten-1']
+  ) {
+    theme.themes.value.light.colors['primary-lighten-1'] =
+      response.data.theme_primary_color_light
+  }
+  if (
+    response.data.theme_primary_color_dark !==
+    theme.themes.value.light.colors['primary-darken-1']
+  ) {
+    theme.themes.value.light.colors['primary-darken-1'] =
+      response.data.theme_primary_color_dark
+  }
+  if (
+    response.data.theme_secondary_color !==
+    theme.themes.value.light.colors.secondary
+  ) {
+    theme.themes.value.light.colors.secondary =
+      response.data.theme_secondary_color
+  }
+  if (
+    response.data.theme_label_color !== theme.themes.value.light.colors.label
+  ) {
+    theme.themes.value.light.colors.label = response.data.theme_label_color
+  }
+})
+</script>
diff --git a/frontend/src/api/theme.js b/frontend/src/api/theme.js
new file mode 100644
index 000000000..972165406
--- /dev/null
+++ b/frontend/src/api/theme.js
@@ -0,0 +1,7 @@
+import repository from './repository'
+
+export default {
+  getTheme() {
+    return repository.get(`/theme/`)
+  },
+}
diff --git a/frontend/src/components/tools/ParametersForm.vue b/frontend/src/components/tools/ParametersForm.vue
index 2c4d14ab6..1393fdfcd 100644
--- a/frontend/src/components/tools/ParametersForm.vue
+++ b/frontend/src/components/tools/ParametersForm.vue
@@ -68,6 +68,16 @@
                     v-model="parameters[param.name]"
                   >
                   </HtmlEditor>
+                  <v-color-picker
+                    v-else-if="param.widget === 'ColorPicker'"
+                    v-model="parameters[param.name]"
+                    :hint="param.help_text"
+                    persistent-hint
+                    :error="formErrors[param.name] !== undefined"
+                    :error-messages="formErrors[param.name]"
+                    density="compact"
+                    variant="outlined"
+                  />
                   <v-text-field
                     v-else
                     v-model="parameters[param.name]"
diff --git a/frontend/src/views/DashboardView.vue b/frontend/src/views/DashboardView.vue
index 1ebb1642d..7b41f1bed 100644
--- a/frontend/src/views/DashboardView.vue
+++ b/frontend/src/views/DashboardView.vue
@@ -1,6 +1,6 @@
 <template>
   <v-toolbar flat>
-    <v-toolbar-title>{{ $gettext('Welcome to Modoboa') }}</v-toolbar-title>
+    <v-toolbar-title>{{ welcomeMsg }}</v-toolbar-title>
   </v-toolbar>
 
   <v-row>
@@ -11,7 +11,21 @@
 </template>
 
 <script setup>
+import { ref } from 'vue'
+import { useGettext } from 'vue3-gettext'
 import NewsFeedWidget from '@/components/admin/dashboard/NewsFeedWidget'
+import parametersApi from '@/api/parameters'
+
+const { $gettext } = useGettext()
+
+const welcomeMsg = ref('')
+
+const response = await parametersApi.getGlobalApplication('core')
+if (response.data.params.custom_welcome_message) {
+  welcomeMsg.value = response.data.params.custom_welcome_message
+} else {
+  welcomeMsg.value = $gettext('Welcome to Modoboa')
+}
 </script>
 
 <style scoped>
diff --git a/modoboa/core/api/v2/serializers.py b/modoboa/core/api/v2/serializers.py
index 5a6d0ec5e..543e4ad30 100644
--- a/modoboa/core/api/v2/serializers.py
+++ b/modoboa/core/api/v2/serializers.py
@@ -141,11 +141,19 @@ class CoreGlobalParametersSerializer(serializers.Serializer):
     )
 
     # Dashboard settings
+    custom_welcome_message = serializers.CharField(required=False)
     rss_feed_url = serializers.URLField(
         allow_blank=True, required=False, allow_null=True
     )
     hide_features_widget = serializers.BooleanField(default=False)
 
+    # Theme settings
+    theme_primary_color = serializers.CharField(default="#046BF8")
+    theme_primary_color_dark = serializers.CharField(default="#0350BA")
+    theme_primary_color_light = serializers.CharField(default="#3688F9")
+    theme_secondary_color = serializers.CharField(default="#F18429")
+    theme_label_color = serializers.CharField(default="#616161")
+
     # Notification settings
     sender_address = lib_fields.DRFEmailFieldUTF8(default="noreply@yourdomain.test")
 
@@ -654,3 +662,12 @@ class NewsFeedEntrySerializer(serializers.Serializer):
     title = serializers.CharField()
     link = serializers.CharField()
     published = serializers.DateTimeField()
+
+
+class ThemeSerializer(serializers.Serializer):
+
+    theme_primary_color = serializers.CharField(default="#046BF8")
+    theme_primary_color_dark = serializers.CharField(default="#0350BA")
+    theme_primary_color_light = serializers.CharField(default="#3688F9")
+    theme_secondary_color = serializers.CharField(default="#F18429")
+    theme_label_color = serializers.CharField(default="#616161")
diff --git a/modoboa/core/api/v2/tests.py b/modoboa/core/api/v2/tests.py
index 7b9a0c10a..50b208106 100644
--- a/modoboa/core/api/v2/tests.py
+++ b/modoboa/core/api/v2/tests.py
@@ -545,6 +545,22 @@ class CapabilitiesAPITestCase(ModoAPITestCase):
         self.assertIn("rspamd", response.json()["capabilities"])
 
 
+class ThemeAPITestCase(ModoAPITestCase):
+
+    def test_get(self):
+        url = reverse("v2:theme")
+        response = self.client.get(url)
+        self.assertEqual(response.status_code, 200)
+        theme = response.json()
+        self.assertEqual(theme["theme_primary_color"], "#046BF8")
+
+        self.set_global_parameter("theme_primary_color", "#FF0000")
+        response = self.client.get(url)
+        self.assertEqual(response.status_code, 200)
+        theme = response.json()
+        self.assertEqual(theme["theme_primary_color"], "#FF0000")
+
+
 class NewsFeedAPIViewTestCase(ModoAPITestCase):
 
     @classmethod
diff --git a/modoboa/core/api/v2/urls.py b/modoboa/core/api/v2/urls.py
index 50b251070..777c2aa72 100644
--- a/modoboa/core/api/v2/urls.py
+++ b/modoboa/core/api/v2/urls.py
@@ -43,4 +43,5 @@ urlpatterns += [
         name="news-feed",
     ),
     path("capabilities/", views.CapabilitiesAPIView.as_view(), name="capabilities"),
+    path("theme/", views.ThemeAPIView.as_view(), name="theme"),
 ]
diff --git a/modoboa/core/api/v2/views.py b/modoboa/core/api/v2/views.py
index 20e55e3cd..269d79224 100644
--- a/modoboa/core/api/v2/views.py
+++ b/modoboa/core/api/v2/views.py
@@ -179,6 +179,27 @@ class CapabilitiesAPIView(APIView):
         return response.Response({"capabilities": get_capabilities()})
 
 
+class ThemeAPIView(APIView):
+    """Return the theme values of this Modoboa instance."""
+
+    permission_classes = [permissions.IsAuthenticated]
+    throttle_classes = [UserLesserDdosUser]
+
+    @extend_schema(responses=serializers.ThemeSerializer)
+    def get(self, request, *args, **kwargs):
+        values = {}
+        params = [
+            "theme_primary_color",
+            "theme_primary_color_dark",
+            "theme_primary_color_light",
+            "theme_secondary_color",
+            "theme_label_color",
+        ]
+        for param in params:
+            values[param] = request.localconfig.parameters.get_value(param)
+        return response.Response(values)
+
+
 class NewsFeedAPIView(APIView):
     """Return list of latest news from configured RSS feed."""
 
diff --git a/modoboa/core/app_settings.py b/modoboa/core/app_settings.py
index 2154fce50..82bb837af 100644
--- a/modoboa/core/app_settings.py
+++ b/modoboa/core/app_settings.py
@@ -99,12 +99,14 @@ GLOBAL_PARAMETERS_STRUCT = collections.OrderedDict(
                         (
                             "allow_special_characters",
                             {
-                                "label": gettext_lazy("Allow special characters for random password"),
+                                "label": gettext_lazy(
+                                    "Allow special characters for random password"
+                                ),
                                 "help_text": gettext_lazy(
                                     "Enable special characters in randomly generated "
                                     "passwords."
                                 ),
-                            }
+                            },
                         ),
                         (
                             "update_password_url",
@@ -478,6 +480,15 @@ GLOBAL_PARAMETERS_STRUCT = collections.OrderedDict(
                 "label": gettext_lazy("Dashboard"),
                 "params": collections.OrderedDict(
                     [
+                        (
+                            "custom_welcome_message",
+                            {
+                                "label": gettext_lazy("Custom welcome message"),
+                                "help_text": gettext_lazy(
+                                    "A welcome message that will be displayed instead the default one"
+                                ),
+                            },
+                        ),
                         (
                             "rss_feed_url",
                             {
@@ -502,6 +513,70 @@ GLOBAL_PARAMETERS_STRUCT = collections.OrderedDict(
                 ),
             },
         ),
+        (
+            "theme",
+            {
+                "label": gettext_lazy("Theme"),
+                "params": collections.OrderedDict(
+                    [
+                        (
+                            "theme_primary_color",
+                            {
+                                "label": gettext_lazy("Primary theme color"),
+                                "help": gettext_lazy(
+                                    "Primary color of the theme (hexadecimal code), used as the background color of the left menu for example"
+                                ),
+                                "widget": "ColorPicker",
+                            },
+                        ),
+                        (
+                            "theme_primary_color_light",
+                            {
+                                "label": gettext_lazy(
+                                    "Primary theme color (lighter version)"
+                                ),
+                                "help": gettext_lazy(
+                                    "Primary color of the theme (hexadecimal code)"
+                                ),
+                                "widget": "ColorPicker",
+                            },
+                        ),
+                        (
+                            "theme_primary_color_dark",
+                            {
+                                "label": gettext_lazy(
+                                    "Primary theme color (darker version)"
+                                ),
+                                "help": gettext_lazy(
+                                    "Primary color of the theme (hexadecimal code)"
+                                ),
+                                "widget": "ColorPicker",
+                            },
+                        ),
+                        (
+                            "theme_secondary_color",
+                            {
+                                "label": gettext_lazy("Secondary theme color"),
+                                "help": gettext_lazy(
+                                    "Secondary color of the theme (hexadecimal code), used as the background color of some buttons for example"
+                                ),
+                                "widget": "ColorPicker",
+                            },
+                        ),
+                        (
+                            "theme_label_color",
+                            {
+                                "label": gettext_lazy("Labels theme color"),
+                                "help": gettext_lazy(
+                                    "Theme color for labels (hexadecimal code)"
+                                ),
+                                "widget": "ColorPicker",
+                            },
+                        ),
+                    ]
+                ),
+            },
+        ),
         (
             "notifications",
             {
diff --git a/modoboa/webmail/lib/sendmail.py b/modoboa/webmail/lib/sendmail.py
index c547204d0..e80995d22 100644
--- a/modoboa/webmail/lib/sendmail.py
+++ b/modoboa/webmail/lib/sendmail.py
@@ -134,7 +134,7 @@ def send_mail(request, attributes: dict, attachments: list) -> tuple[bool, str |
                 {
                     "backend": "modoboa.lib.smtp_backend.OAuthBearerEmailBackend",
                     "username": request.user.email,
-                    "password": request.auth,
+                    "password": str(request.auth),
                 }
             )
         else: